Biomimic artificial neuron
An artificial neuron is formed from an input subcircuit, a capacitor free leaky integrator subcircuit, and an output switching subcircuit. The input subcircuit is configured to supply a pulsed input signal. The capacitor free leaky integrator subcircuit is configured to supply a parasitic capacitance and to utilize the parasitic capacitance to provide differing time constants for the rising and falling edges of an output signal produced in response to the pulsed input signal. The output switching subcircuit s configured to, upon receipt of a sufficient output signal from the capacitor free leaky integrator subcircuit, switch off the input subcircuit and to release a neuron firing signal.
1. An artificial neuron, comprising a plurality of tangible electronic elements interconnected to form:
an input subcircuit for supplying a pulsed input signal;
a capacitor free leaky integrator subcircuit operable to supply a parasitic capacitance and to utilize the parasitic capacitance to provide differing time constants for the rising and falling edges of an output signal produced in response to the pulsed input signal; and
an output switching subcircuit operable upon receipt of a sufficient output signal from the capacitor free leaky integrator subcircuit to switch off the input subcircuit and to release a neuron firing signal.
2. The artificial neuron of claim 1 , wherein the capacitor free leaky integrator subcircuit comprises:
a capacitor-free, non-linear delay resistor having a parasitic capacitance; and
a capacitor-free amplifier tied to the delay resistor wherein the amplifier utilizes the parasitic capacitance of the delay resistor to provide the differing time constants for the rising and falling edges of the output signal produced in response to the pulsed input signal.
3. The artificial neuron of claim 2 , wherein the delay resistor includes a first transistor and a second transistor each having source, a drain, and a gate; and wherein
for the first transistor:
the source defines an input for the leaky integrator; and
the drain is tied to the amplifier; and
for the second transistor:
the source is tied to the drain of the first transistor; and
the drain is tied to the capacitor-free amplifier and an output of the capacitor free leaky integrator.
4. The artificial neuron of claim 1 , wherein the output switching subcircuit comprises an inverting Schmidt trigger.
5. The artificial neuron of claim 1 , wherein the input subcircuit for supplying a pulsed input signal comprises an input subcircuit for supplying a pulsed excitatory signal and a pulsed inhibitory signal.
6. The artificial neuron of claim 1 , wherein an increased inhibitory signal causes a decrease in the time constant provided by the capacitor-free leaky integrator.